Orthodontic brackets are used with arch wires and elastomeric chains or other force transmitting members to apply corrective forces on misaligned teeth. The brackets, which are mounted on the teeth, typically include an underlying base portion, which abuts the tooth surface, and an outer portion. The outer portion includes a slot for receiving the arch wire and wing members to facilitate attachment of elastomeric chains or ligatures. Brackets may also include hook members for attachment of additional force transmitting devices.
Conventional brackets generally known as "single wing" brackets have an outer portion comprising a single vertically-oriented bar with a slot forward therein for receiving the arch wire. Single wing brackets may also include a pair of horizontal extension members for rotation control during tooth movement.
Conventional brackets generally known as twin-MDA brackets have an outer portion comprising a pair of parallel, vertically-oriented bars with a slot formed in each bar to receive the arch wire.
Many conventional brackets fail to provide adequate rotation control during tooth movement or true vertical force transmission between brackets mounted on upper and lower teeth. As a result, use of these brackets may cause the creation of gaps between teeth like, for example, gaps at the cuspid bicuspid incisal interface. These gaps are aesthetically undesirable and may affect long term dental health.
Accordingly, one object of this invention is to provide brackets having improved rotation control during tooth movement.
Another object of this invention is to provide brackets that when placed on upper and lower teeth enable generally true vertical force transmission between the upper and lower teeth.